// Directions
// Write a test that scrolls through a list of items
// Record the performance of the app
// Save the results to disk
// Run the test
// Review the results
import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Counter App',
      home: MyHomePage(title: 'Counter App Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  List<String> items = List<String>.generate(10000, (i) => "Item $i");

  void _incrementCounter() {
    setState(() {
      items.add("Item ${items.length}");
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: ListView.builder(
        key: Key('long_list'),
        itemCount: items.length,
        itemBuilder: (context, index) {
          return ListTile(
            title: Text('${items[index]}', key: Key('item_${index}_text'),),
          );
        },
      ),
      floatingActionButton: FloatingActionButton(
        // Provide a Key to this the button. This allows us to find this
        // specific button and tap it inside the test suite.
        key: Key('increment'),
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}